The invention is in the field of vacuum spindles for pick and place machines and generally is directed to automated exchange of tips of a vacuum spindle according to features, such as size and shape, of a component to be handled by the vacuum spindle.
Heretofore, vacuum spindles employing changeable tips have relied on friction detents biased into engagement between the spindle and tip to maintain their connection. Changing such nozzles has been accomplished by moving the spindle to position the already attached tip in an empty pocket of a tool changer, grasping and holding the tip mechanically in the tool changer, and retracting the spindle away from the pocket so as to overcome the force of the detent and thus strip the tip from the spindle. Next, the spindle would be repositioned over a pocket housing a selected replacement nozzle, and the spindle would be moved down with an engagement force sufficient to overcome the force of the detent and allow attachment of the nozzle and spindle.
This prior art connection is prone to a rotational "backlash" between the nozzle and spindle which is due, at least in part, to tolerances of the detent-type connection therebetween. Also, this type of connection is prone to so-called "runout" or rocking of the nozzle on the spindle such that the longitudinal axis of the nozzle is tilted relative to the longitudinal axis of the spindle.
These undesirable conditions generally are the result of limitations of the detent force which must be sufficient to hold the nozzle and spindle together and also be light enough to be overcome during the attachment and detachment process of placement machines described above.
Thus, an object of the invention is to improve the connection between the spindle and removable nozzles so that there is no angular backlash of the nozzle about the longitudinal axis of the spindle while a component is being held by the vacuum.
Also, it is an object of the invention to provide an improvement in the connection between the nozzle and spindle which substantially eliminates so-called "runout" or tilting of the longitudinal axis of the nozzle relative to the longitudinal axis of the spindle.
Additionally, it is an object of the invention to provide a connection between the nozzle and spindle by using an easily applicable and removable force of connection which is much greater than conventional detent-type forces while a component is being held by a vacuum.
Further, it is an object of the invention to eliminate the need for the mechanical separation and attachment forces during the exchange of nozzles between the vacuum spindle and nozzle replacement reservoir.
These and other objects of the invention will become more apparent from the remaining disclosure.